Virgin Media is currently under investigation by the Advertising Standards Authority, following a complaint over its claimed broadband speeds.

T3 was told by the ASA that it has an ongoing formal investigation into Virgin Media with regards to adverts which claim it provides 'the UK's fastest broadband.'

BT has challenged whether the claim is misleading and can be substantiated.

Matt Wilson from the ASA told us: “The outcome of an upheld ASA investigation, i.e. where an advertiser if found in breach of the Advertising Code is that the ad has to be withdrawn and is prohibited from appearing again. We have and will continue to clamp down on any advertiser that makes misleading advertising claims about its broadband services.”

The organisation will release its findings 'imminently'.

We contacted Virgin Media for comment, and a spokesperson told us: “Virgin Media delivers broadband speeds of up to 100Mb, soon to be 120Mb, more than 13 times faster than the UK's average. And we deliver on the speeds we promise, consistently proven by Ofcom.”

The ASA has upheld complaints against Virgin's broadband speed claims in the past. In 2009 B Sky B challenged whether the claim "10 out of 10 homes with our fibre optic broadband can get 20Mb" was misleading, because it did not believe there was sufficient capacity in Virgin's network to provide all customers with 20Mb at the same time.

And in 2011 BT challenged Virgin adverts which stated "Ofcom have proven our fibre optic broadband is around twice as fast as BT."